1. Field of the Invention
The present invention relates to an ignition plug socket structure for connecting an ignition plug provided for an internal combustion engine to an ignition coil for generating a high tension via a high tension cord, and more specifically to an ignition plug socket structure easy to be connected to the ignition plug and difficult to be vibrated after having been connected to the ignition plug.
2. Description of the Prior Art
In general, an ignition plug socket is used to supply a high tension generated by an ignition coil to an ignition plug provided for an automotive vehicle. In this case, an ignition plug socket is attached to one end of a high tension cord, and a female plug socket terminal provided at one end of the plug socket is mated with a male ignition plug terminal provided within a hole formed in an engine body.
In more detail, with reference to FIG. 1, an ignition plug 1 having an ignition electrode (not shown) and projecting into a combustion chamber (not shown) is fixed via thread to a bottom of an ignition plug socket mounting hole 2 formed in an engine body 3. An insulating plug socket protective cover 4 is disposed on the inner circumference of this plug socket mounting hole 2, and an ignition plug terminal 7 is fixed to the ignition plug 1.
On the other hand, an ignition plug socket 20A comprises an ignition plug socket body 9, and a plug socket terminal 5 provided within the plug socket body 9 and connected to one end of a noise prevention high tension cord 6 whose other end is connected to an ignition coil (not shown). This plug socket terminal 5 is mated with the ignition plug terminal 7 near the internal end of the ignition plug socket 20A. Further, an upper rubber cap 10 formed with a socket mounting groove 11 is attached to top of the ignition plug socket 20A to hold and guide the high tension cord 6.
Therefore, when the ignition plug socket 20A is mounted on the engine body to connect the high tension cord 6 to the ignition plug 1, the ignition plug socket 20A is inserted into the plug socket mounting hole 2 via the insulating plug socket protective cover 4 so that the plug socket terminal 5 is engaged with the ignition plug terminal 7 at the internal end of the plug socket 20A and simultaneously the socket mounting groove 11 is engaged with the top end of the plug socket protective cover 4 at the external end of the plug socket 20A.
In the prior-art ignition plug socket 20A, however, since the plug socket mounting hole 2 is relatively deep, there exists a problem in that it is difficult to connect the socket terminal 5 with the ignition plug terminal 7, that is, to align the axial center of the plug socket 20A with that of the ignition plug 1. This is because the lower end of the plug socket body 9 tends to be brought into contact with the upper end of the ignition terminal 7 of the ignition plug 1. In addition, in the prior-art ignition plug socket 20A, since the ignition plug socket 20A is fixed to the engine body 3 at only the external position (where the plug socket protective cover 4 is engaged with the socket mounting groove 11 of the upper rubber cap 10) and the inner position (where the socket terminal 5 is engaged with the plug terminal 7), there exists another problem in that after the plug socket 20A has been mounted on the engine, vibration is directly transmitted to the plug socket when the engine is running or the vehicle is travelling, so that the plug socket 20A is damaged or removed from the engine body 3.